Tophaceous Gout of the Lumbar Spine Mimicking Infectious Spondylodiscitis and Epidural Abscess

Objectives: We report a case of surgically proven tophaceous gout of the lumbar spine at the L5-S1 level in a 43-year-old man that mimicked infectious spondylodiscitis and epidural abscess on magnetic resonance (MR) images. Summary of Literature Review: Some patients have chronic back pain with an epidural mass. Among the many causes of epidural masses, tophaceous gout of the lumbar spine is very rare. Materials and Methods: A 43-year-old man presented with fever and chronic back pain with radiating pain. In an MR image of L4-5, an abnormal subcutaneous mass was found in the posterior epidural space. The subcutaneous mass was isointense on T1-weighted images compared with the intervertebral disc, and focally and strongly hyperintense and heterogeneous on T2-weighted images. After the intravenous administration of gadolinium contrast, the mass was fairly homogenous, with a low signal intensity and without enhancement. With the diagnosis of infective spondylitis with epidural abscess, we performed a decompressive mass resection. Results: The pathologic examination revealed multinuclear giant cells and amorphous crystalline fibrous tissue. The lesion was diagnosed as tophaceous gout. Conclusions: This case underscores the importance of considering tophaceous gout in the differential diagnosis of an epidural mass in a patient with chronic back pain.